Mutations in the B30.2 and the central helical scaffold domains of pyrin differentially affect inflammasome activation

Familial Mediterranean Fever (FMF) is the most common monogenic autoinflammatory disorder. FMF is caused by mutations in the MEFV gene, encoding pyrin, an inflammasome sensor. The best characterized pathogenic mutations associated with FMF cluster in exon 10. Yet, mutations have been described along the whole MEFV coding sequence. Exon 10 encodes the B30.2 domain of the pyrin protein, but the function of this human-specific domain remains unclear. Pyrin is an inflammasome sensor detecting RhoA GTPase inhibition following exposure to bacterial toxins such as TcdA. Here, we demonstrate that the B30.2 domain is dispensable for pyrin inflammasome activation in response to this toxin. Deletion of the B30.2 domain mimics the most typical FMF-associated mutation and confers spontaneous inflammasome activation in response to pyrin dephosphorylation. Our results indicate that the B30.2 domain is a negative regulator of the pyrin inflammasome that acts independently from and downstream of pyrin dephosphorylation. In addition, we identify the central helical scaffold (CHS) domain of pyrin, which lies immediately upstream of the B30.2 domain as a second regulatory domain. Mutations affecting the CHS domain mimic pathogenic mutations in the B30.2 domain and render the pyrin inflammasome activation under the sole control of the dephosphorylation. In addition, specific mutations in the CHS domain strongly increase the cell susceptibility to steroid catabolites, recently described to activate pyrin, in both a cell line model and in monocytes from genotype-selected FMF patients. Taken together, our work reveals the existence of two distinct regulatory regions at the C-terminus of the pyrin protein, that act in a distinct manner to regulate positively or negatively inflammasome activation. Furthermore, our results indicate that different mutations in pyrin regulatory domains have different functional impacts on the pyrin inflammasome which could contribute to the diversity of pyrin-associated autoinflammatory diseases.

Use of biologics to treat relapsing and/or refractory polyarteritis nodosa: data from a European collaborative study

OBJECTIVES

To describe the effectiveness and safety of biologics for the treatment of relapsing and/or refractory polyarteritis nodosa (PAN).

METHODS

A retrospective European collaborative study was conducted in patients with PAN who received biologics for relapsing and/or refractory disease.

RESULTS

Forty-two patients with PAN received a total of 53 biologic courses, including TNF-α blockers in 15 cases, rituximab (RTX) in 18 cases, tocilizumab (TCZ) in 10 cases and other biologics in 10 cases. TNF-α blockers and TCZ were mainly used for refractory diseases whereas RTX was mainly initiated for relapsing disease. After a median follow-up of 29 (8-50) months, remission, partial response, treatment failure and treatment discontinuation due to severe adverse events occurred in, respectively, 40%, 13%, 40% and 7% of patients receiving TNF-α blockers, 50%, none, 30% and 20% of TCZ recipients, and 33%, 11%, 56% and none of the RTX recipients. No remission was noted in patients treated with other biologics. Severe adverse events were observed in 14 (28%) patients without significant differences between the three biologics, leading to early biologics discontinuation in only three cases.

CONCLUSION

These results suggest that TCZ may be effective in relapsing and/or refractory PAN. Our data warrant further study to confirm these findings.

Development and validation of a quality of life measurement scale specific to hereditary hemorrhagic telangiectasia: the QoL-HHT

Background

Hereditary hemorrhagic telangiectasia (HHT) disease is a rare genetic disorder with symptoms and complications that can significantly affect patients’ daily lives. To date, no scale has been validated to assess the specific symptoms of this disease on the quality of life (QOL) of HHT patients. This makes it difficult for clinicians to accurately measure the quality of life of patients with HHT. The present study aims to develop and validate a QOL measurement tool specific to HHT disease: the QOL questionnaire in HHT (QoL-HHT).

Methods

A quantitative, non-interventional, multi-center study involving HHT patients in twenty French HHT expert centers was conducted. A calibration sample of 415 HHT patients and a validation sample of 228 HHT patients voluntarily participated in the study. Data were analyzed using exploratory factor analysis (EFA), confirmatory factor analysis (CFA), Exploratory Structural Equation Modeling (ESEM) analyses, reliability analyses, and correlational analyses.

Results

The EFA, CFA and ESEM results allowed us to provide evidence of the factorial structure of a questionnaire composed of 24 items measuring 6 domains of QOL: Physical limitations, social relationships, concern about bleeding, relationship with the medical profession, experience of symptoms, and concern about the evolution of the disease. Cronbach’s alpha coefficients (> 0.70) demonstrated reliable internal consistency of all the QoL-HHT scores (dimensions). The results of the test–retest provided further evidence of the reliability of the QOL-HHT scores over time. Correlational analyses provided evidence for the convergent validity of the QoL-HHT scores.

Conclusions

We developed a simple and quick self-assessment tool to measure quality of life specific to HHT disease. This study demonstrated reliability and validity of our QoL-HHT scores. It is a very promising tool to evaluate the impact of HHT disease on all aspects of the quality of life of HHT patients in order to offer them individualized medico-psycho-social support.

Trial registration: ClinicalTrials, NCT03695874. Registered 04 October 2018, https://www.clinicaltrials.gov/ct2/show/NCT03695874

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02426-2.

Myeloproliferative neoplasms and clonal hematopoiesis in patients with giant cell arteritis: a case-control and exploratory study

OBJECTIVES

Giant cell arteritis (GCA) is a large vessel vasculitis for which triggering factors remain unknown. Clonal hematopoiesis (CH) was associated with atherosclerosis through the induction of inflammation in myeloid cells, and data suggest that CH expansion and inflammation may support each other to induce a proinflammatory loop. Our objective was to describe the impact of JAK2p.V617F-mutated myeloproliferative neoplasms (MPN) on GCA and to screen MPN-free patients for CH mutations.

METHODS

We performed a retrospective case-control study comparing characteristics of 21 GCA patients with MPN and 42 age and gender-matched GCA patients without MPN. Also, 18 GCA patients were screened for CH through Next Generation Sequencing.

RESULTS

The most frequent associated MPN was essential thrombocythemia (ET) (n = 11). Compared to controls, GCA patients with MPN had less frequent cephalic symptoms (71.4 vs. 97.6%, p = 0.004) and higher platelets count at baseline [485 (346-586) vs. 346 [IQR 296-418] x 109/L, p = 0.02). There was no difference between groups for other clinical features. Overall survival was significantly shorter in patients with MPN compared to controls [HR 8.2 (95% CI 1.2-56.6), p = 0.03]. Finally, screening for CH using NGS in 15 GCA patients without MPN revealed CH in 33%.

CONCLUSION

GCA patients with MPN display higher platelets count and shorter overall survival than controls. This association could not be fortuitous given the possible pathophysiological relationship between the two diseases. CH was found in one third of GCA patients, which may be higher than the expected prevalence for similar age, what should be confirmed in a larger cohort.

Interleukin 6 receptor inhibition in primary Sjögren syndrome: a multicentre double-blind randomised placebo-controlled trial

OBJECTIVES

No immunomodulatory drug has been approved for primary Sjögren's syndrome, a systemic autoimmune disease affecting 0.1% of the population. To demonstrate the efficacy of targeting interleukin 6 receptor in patients with Sjögren's syndrome-related systemic complications.

METHODS

Multicentre double-blind randomised placebo-controlled trial between 24 July 2013 and 16 July 2018, with a follow-up of 44 weeks, involving 17 referral centres. Inclusion criteria were primary Sjögren's syndrome according to American European Consensus Group criteria and score ≥5 for the EULAR Sjögren's Syndrome Disease activity Index (ESSDAI, score of systemic complications). Patients were randomised to receive either 6 monthly infusions of tocilizumab or placebo. The primary endpoint was response to treatment at week 24. Response to treatment was defined by the combination of (1) a decrease of at least 3 points in the ESSDAI, (2) no occurrence of moderate or severe activity in any new domain of the ESSDAI and (3) lack of worsening in physician's global assessment on a Visual Numeric Scale ≥1/10, all as compared with enrolment.

RESULTS

110 patients were randomised, 55 patients to tocilizumab (mean (SD) age: 50.9 (12.4) years; women: 98.2%) and 55 patients to placebo (54.8 (10.7) years; 90.9%). At 24 weeks, the proportion of patients meeting the primary endpoint was 52.7% (29/55) in the tocilizumab group and 63.6% (35/55) in the placebo group, for a difference of -11.4% (95% credible interval -30.6 to 9.0) (Pr[Toc >Pla]=0.14).

CONCLUSION

Among patients with primary Sjögren's syndrome, the use of tocilizumab did not improve systemic involvement and symptoms over 24 weeks of treatment compared with placebo.

TRIAL REGISTRATION NUMBER

NCT01782235.

Safety of hydroxychloroquine and darunavir or lopinavir in COVID-19 infection

BACKGROUND

Combination therapy with hydroxychloroquine and darunavir/ritonavir or lopinavir/ritonavir has been suggested as an approach to improve the outcome of patients with moderate/severe COVID-19 infection.

OBJECTIVES

To examine the safety of combination therapy with hydroxychloroquine and darunavir/ritonavir or lopinavir/ritonavir.

METHODS

This was an observational cohort study of patients hospitalized for COVID-19 pneumonia treated with hydroxychloroquine and darunavir/ritonavir or lopinavir/ritonavir. Clinical evaluations, electrocardiograms and the pharmacokinetics of hydroxychloroquine, darunavir and lopinavir were examined according to clinical practice and guidelines.

RESULTS

Twenty-one patients received hydroxychloroquine with lopinavir/ritonavir (median age 68 years; 10 males) and 25 received hydroxychloroquine with darunavir/ritonavir (median age 71 years; 15 males). During treatment, eight patients (17.4%) developed ECG abnormalities. Ten patients discontinued treatment, including seven for ECG abnormalities a median of 5 (range 2-6) days after starting treatment. All ECG abnormalities reversed 1-2 days after interrupting treatment. Four patients died within 14 days. ECG abnormalities were significantly associated with age over 70 years, coexisting conditions (such as hypertension, chronic cardiovascular disease and kidney failure) and initial potential drug interactions, but not with the hydroxychloroquine concentration.

CONCLUSIONS

Of the patients with COVID-19 who received hydroxychloroquine with lopinavir or darunavir, 17% had ECG abnormalities, mainly related to age or in those with a history of cardiovascular disease.

Management and outcomes of 27 pregnancies in women with myeloproliferative neoplasms

Introduction: Philadelphia-negative myeloproliferative neoplasms (MPNs) greatly increase the risk of maternal and fetal complications during pregnancy. Currently, international agreements regarding the management of these women are lacking.Patients and methods: Our study aimed to assess the current management and outcomes of MPN pregnancies in a French cohort. We retrospectively analyzed 27 pregnancies in women with MPNs that were associated with a specific mutation. Nineteen pregnancies in nine women with essential thrombocythemia and eight pregnancies in five women with polycythemia vera were identified.Results: Our study showed 70% live births, but only 30% uneventful pregnancies. Fetal complications were mainly early spontaneous abortions (22%), fetal growth restriction (15%), and premature delivery (15%). Maternal issues were divided between thrombosis (15%) and hemorrhages (11%). High rates of preeclampsia and hemolysis, elevated liver enzymes, and low platelet count syndrome (15%) were reported. Uterine artery Doppler was performed in 70% pregnancies. Abnormal Doppler results were found in 43% pregnancies. Pregnancies with high platelet counts and packed cell volume remaining static or increasing ended with fetal death and utero-placental dysfunction. According to expert consensus, most of the pregnancies (67%) could be stratified in the high risk group and had a bad obstetrical outcome, with 50% standard-risk pregnancies versus 22% high-risk pregnancies that were uneventful. Higher risk pregnancies were prescribed heparin and/or interferon α in 72%.Conclusions: The prognosis of these pregnancies remains very bad and may be improved by a more effective collaboration between specialists as well as a therapeutic intensification including heparin and interferon α.

Neutrophil-derived mitochondrial DNA promotes receptor activator of nuclear factor κB and its ligand signalling in rheumatoid arthritis

Objectives

Mitochondrial DNA (mtDNA) contains sequestered damage-associated molecular patterns that might be involved in osteoimmunological pathogenesis of RA. Here, we aimed to investigate the cellular source of mtDNA and its role in RANK ligand (RANKL) expression by RA SF neutrophils.

Methods

The gene expression signature of SF neutrophils was examined by proteomic quantitative analysis. Levels of mtDNA in circulating and SF neutrophils from RA patients and OA control subjects were assessed by real-time PCR. Purified neutrophils were challenged in vitro with Toll-like receptor agonists as well as mtDNA. RANKL expression by neutrophils was studied by flow cytometry.

Results

SF neutrophils from RA patients displayed a gene expression signature of oxidative stress. This stress signature was associated with the release of mtDNA in SF as observed by a significant increase of mtDNA in the SF of RA patients compared with OA patients. mtDNA in RA SF was correlated with systemic inflammation as assessed by CRP concentrations. We also showed that mtDNA drives neutrophil RANKL expression to the same extent as Toll-like receptor agonists.

Conclusion

Our data identify SF neutrophils as a cellular source of mtDNA that leads to a subsequent expression of RANKL. This highlights the important role of neutrophils in RA osteoimmunology.